Field of the Invention
The present invention relates generally to snow plows for use with light and medium duty trucks, and more particularly to an improved snow plow with a frame which uses an in-line design to eliminate the presence of rotational or torsional force in the frame members of the snow plow, which design provides an improved degree of ground clearance as well.
Once the exclusive domain of municipality-operated heavy trucks, snow plows have been used with light and medium duty trucks for decades. As would be expected in any area of technology which has been developed for that period of time, snow plows for light and medium duty trucks have undergone tremendous improvement in a wide variety of ways over time, evolving to increase both the usefulness of the snow plows as well as to enhance the ease of using them. The business of manufacturing snow plows for light and medium duty trucks has been highly competitive, with manufacturers of competing snow plows differentiating themselves based on the features and enhanced technology that they design into their products.
There have been a wide variety of frame designs which have been used to mount straight (non-V-shaped) snow plow blades onto a vehicle. The first requirement of the design of a snow plow frame is that it be sufficiently strong to support the blade when snow is being plowed. This strength must thus restrict any unwanted movement of the blade with respect to the frame. It must achieve this requirement without being excessively heavy, and it must also provide sufficient ground clearance to prevent the bottom of the frame from contacting the ground, even in hilly or rough terrain. The ground clearance is a function of the height of the truck, the position of the portion of the hitch mounted on the truck (typically under the front bumper), and the design of the frame.
The frame of a snow plow is mounted onto a truck, and it supports a swing frame at the front thereof upon which the blade of the snow plow is mounted. There are typically hydraulic cylinders located between the snow plow frame and the right and left sides of the swing frame which are used to pivot the swing frame and the blade mounted thereon. Typically, the swing frame is pivotally mounted on the top side of the snow plow frame. Since the blade must be supported at a relatively low position, and since the snow plow frame is located below the swing frame, the ground clearance on most plow designs is not optimal. In addition, the pivot point in such snow plow designs will always be subject to a rotational force in addition to a force which is horizontal to the ground.
It is accordingly the primary objective of the present invention that it provide a snow plow frame having an in-line swing frame support design wherein the snow plow frame and the swing frame both are in the same horizontal axis, so that the predominant line of force through each will be from the front of the snow plow to the back. It is a related objective of the in-line snow plow frame of the present invention that it completely eliminate the rotational force component on the pivot point between the swing frame and the snow plow frame. It is a further related objective of the in-line snow plow frame of the present invention that the snow plow frame and the swing frame together present a low profile to allow the snow plow to have a relatively high ground clearance.
It is a further objective of the in-line snow plow frame of the present invention that it be of high strength, yet that it also be light of weight. It is still another objective of the in-line snow plow frame of the present invention that it have structural integrity at least equal to previously known snow plow frame designs. It is a still further objective of the in-line snow plow frame of the present invention that its in-line design not compromise rigidity, but rather that the design provide an increased level of rigidity.
The in-line snow plow frame of the present invention must also be of construction which is both durable and long lasting, and it should also require little or no maintenance to be provided by the user throughout its operating lifetime. In order to enhance the market appeal of the in-line snow plow frame of the present invention, it should also be of inexpensive construction to thereby afford it the broadest possible market. Finally, it is also an objective that all of the aforesaid advantages and objectives of the in-line snow plow frame of the present invention be achieved without incurring any substantial relative disadvantage.
The disadvantages and limitations of the background art discussed above are overcome by the present invention. With this invention, a snow plow frame design which supports the swing frame from both the top and the bottom thereof is presented. It will at once be appreciated by those skilled in the art that by so doing the rotational component of the force on the pivot point will be virtually eliminated. The key to implementing this design is ensuring that the snow plow frame remains sufficiently rigid.
The in-line snow plow frame of the present invention is fundamentally A-shaped, with the top of the xe2x80x9cAxe2x80x9d being located at the front of the snow plow, and the bottom of the xe2x80x9cAxe2x80x9d being located at the rear of the snow plow. The plow frame is based upon two spaced-apart A-shaped steel plates which resemble a portion of the capital letter xe2x80x9cA,xe2x80x9d with the portions of the sides of the xe2x80x9cAxe2x80x9d above the crossbar of the xe2x80x9cAxe2x80x9d being absent. The two A-shaped steel plates are supported in their spaced-apart relationship on four portions of their sides. On both sides of the xe2x80x9cA,xe2x80x9d side walls extend between the two A-shaped steel plates from the bottom of the xe2x80x9cAxe2x80x9d about two-thirds of the way toward the top of the xe2x80x9cA.xe2x80x9d Two other side walls extend laterally between the ends of the first two side walls.
Located in the two A-shaped steel plates near the top of the xe2x80x9cAxe2x80x9d are two corresponding apertures, and two swing frame pivots made of steel tubing are welded into the two apertures and extend from the side of each of the A-shaped steel plates which is opposite the other A-shaped steel plate. Also located on the side of each of the two A-shaped steel plates which is opposite the other A-shaped steel plate are ribs which extend from the swing frame pivots to the outsides of the xe2x80x9cA,xe2x80x9d and then along a portion of the A-shaped steel plates. These ribs thus reinforce both the swing frame pivots and the portions of the two A-shaped steel plates which do not have side walls extending therebetween. It is this area between the two A-shaped steel plates where the swing frame will be located.
The swing frame itself is based upon a rectangular steel swing frame tube, which has a pivot made of steel tubing extending between two opposite sides of the swing frame in a location intermediate the ends of the swing frame. The swing frame is located between the two A-shaped steel plates of the snow plow frame, and is pivotally mounted with a pivot pin extending between the swing frame pivots, with the pivot in the swing frame located therebetween. The swing frame is free to pivot, restricted only by the side plate located nearest the top of the xe2x80x9cA.xe2x80x9d It will thus be appreciated by those skilled in the art that the snow plow frame and the swing frame are located along a common horizontal axis, rather than having the swing frame atop the snow plow frame as in previously known frame designs.
The swing frame has support members mounted at each end for pivotally supporting the snow plow blade about a horizontal axis. Also located on the swing frame near opposite ends thereof is a bracket for mounting one end of one or two trip springs, the other ends of which trip springs will be mounted to the snow plow blade. The swing frame is operated by two hydraulic cylinders on the right and left sides of the snow plow frame. The hydraulic cylinders are each mounted at one end thereof onto mounts located on the sides of the snow plow frame near the bottoms of the xe2x80x9cA,xe2x80x9d and at the other ends thereof to mounting plates located on the rear-facing side of the swing frame.
The A-frame is mounted onto a hitch frame which in turn is located on a truck with a mounting apparatus located at the bottoms of the xe2x80x9cA.xe2x80x9d The portions of the steel plate which are removed from the two A-shaped steel plates between the sides of the xe2x80x9cAxe2x80x9d and above the crossbar of the xe2x80x9cAxe2x80x9d which are removed provide the location for a mechanism which will facilitate both the installation of the snow plow onto the truck and the raising and lowering of the snow plow blade. Additional components are mounted on the snow plow frame to facilitate the installation of the mechanism referred to herein.
It may therefore be seen that the present invention teaches a snow plow frame having an in-line swing frame support design wherein the snow plow frame and the swing frame are both in the same horizontal axis, so that the predominant line of force through each is from the front of the snow plow to the back. The in-line snow plow frame of the present invention completely eliminates the rotational force component on the pivot point between the swing frame and the snow plow frame. The snow plow frame and the swing frame of the in-line snow plow frame of the present invention together present a low profile to allow the snow plow to have a relatively high ground clearance.
The in-line snow plow frame of the present invention is of high strength, yet it is light of weight. The structural integrity of the in-line snow plow frame of the present invention is superior to that of previously known snow plow frame designs. The in-line design of the in-line snow plow frame of the present invention does not in any way compromise rigidity, but rather provides an increased level of rigidity.
The in-line snow plow frame of the present invention is of a construction which is both durable and long lasting, and which will require little or no maintenance to be provided by the user throughout its operating lifetime. The in-line snow plow frame of the present invention is also of inexpensive construction to enhance its market appeal and to thereby afford it the broadest possible market. Finally, all of the aforesaid advantages and objectives of the in-line snow plow frame of the present invention are achieved without incurring any substantial relative disadvantage.